Underwater structure low-noise damping laying method based on ship three-dimensional acoustic elasticity

Abstract

The invention relates to an underwater structure low-noise damping laying method based on ship three-dimensional acoustic elasticity. The method comprises the steps that S1, a full-three-dimensional dynamic model is established for a structure; s2, adopting a sound radiation characteristic frequency modal identification method; s3, constructing an attention feature mode; s4, constructing an attention mode and a corresponding weight coefficient; s5, constructing a unit damping efficiency data set; s6, outputting the laying damping thickness of the corresponding area according to the damping loss efficiency from large to small for the unit damping efficiency data set; and S7, obtaining structure sound radiation under the excitation load of the laid structure. The method is compact and reasonable in structure and convenient to operate, optimization design of ship structure damping laying is achieved by adopting a full-three-dimensional dynamic model and a modal recognition method and constructing a unit damping efficiency data set and other advanced means, the suppression capacity of the damping structure on vibration and noise can be more comprehensively reflected, and the method is suitable for the ship structure damping laying. The invention provides a more efficient and accurate damping laying optimization method.

Description

Technical Field

[0001] The invention relates to the technical field of ship structure vibration reduction and noise reduction, in particular to a low-noise damping laying method for underwater structures based on three-dimensional acoustic elasticity of ships. Background Art

[0002] The damping and vibration reduction treatment of ship structures by laying viscoelastic damping materials is widely used in engineering. Generally, damping layers are laid at locations with large vibrations such as excitation sources based on experience. However, whether this area has the same great impact on sound radiation and how to lay damping layers more effectively to achieve the best effect have always been the focus of attention in the engineering and academic circles. Traditional methods often rely on empirical judgment and lack scientific optimization guidance, resulting in unsatisfactory results in the laying of damping layers. Therefore, it is particularly important to explore a more efficient and accurate damping laying optimization method.

[0003] The optimization problem of damping laying has always been a hot research issue. However, judging from the current research results, the optimization design is generally carried out through topology optimization methods (variable density method, variable thickness method, etc.), but there are still the following shortcomings: the optimization efficiency for complex models is low, and the introduction of variables in the thickness direction will further significantly increase the calculation overhead. These shortcomings limit the widespread application of traditional optimization methods in actual engineering, especially when dealing with complex ship structures, calculation efficiency and accuracy become problems that need to be solved urgently.

[0004] To this end, we propose a low-noise damping laying method for underwater structures based on the three-dimensional acoustic elasticity of ships. Summary of the invention

[0005] In view of the shortcomings of the above-mentioned existing production technology, the applicant provides a method for low-noise damping installation of underwater structures based on the three-dimensional acoustic elasticity of ships, thereby realizing an optimized design of damping installation of ship structures.

[0006] The technical solution adopted by the present invention is as follows:

[0007] 1. A method for laying low noise damping for underwater structures based on three-dimensional acoustic elasticity of ships, comprising:

[0008] S1: Establish a full three-dimensional dynamic model for the structure, conduct three-dimensional acoustic elastic analysis of the ship based on the actual working load excitation, and obtain the structural acoustic radiation under the original structural excitation load;

[0009] S2: The acoustic radiation characteristic frequency mode identification method based on the ship's three-dimensional acoustic elastic method is adopted;

[0010] S3: Construct the characteristic mode of interest based on actual engineering needs mode = {mode1...mode i}, corresponding weight A={A1...Ai} and the amount of damping material laid m0;

[0011] S4: After constructing the mode of interest and the corresponding weight coefficient based on actual engineering needs, we can construct a data sample set of structural unit strain energy, output the unit modal strain energy of each unit of the structure, and perform normalization and weighting processing;

[0012] S5: construct a unit damping efficiency data set, and output the increment of the strain energy loss of the structural unit in each unit damping thickness unit area of ​​all units in the design area;

[0013] S6: Output the damping thickness of the corresponding area according to the damping loss efficiency from large to small for the unit damping efficiency data set, and construct the structural damping laying area data set according to the set damping material weight constraint;

[0014] S7: Based on the modal strain energy method, a generalized damping matrix is ​​formed [b], and a three-dimensional acoustic elastic analysis of the ship is carried out to obtain the structural sound radiation under the excitation load of the structure after laying.

[0015] Furthermore, in S2, the principal coordinate response of each mode and the attached water damping are used to approximate the radiated sound power of a single mode.

[0016]

[0017] Where P(ω) is the radiated acoustic power, q is the principal coordinate response, and B is the attached water damping matrix. The superscript “*” indicates conjugation.

[0018] Furthermore, the processing method in S4 further includes the following steps:

[0019] S4.1: Based on the modal characteristics of interest, output the modal strain energy of the structure's required layout area elements

[0020] S4.2: Volume normalization of the element modal strain energy,

[0021] S4.3: If the number of modes of interest is greater than 1, energy normalization is required. where sum(elen_all i ) is the sum of the strain energies of all elements in the corresponding modal structure;

[0022] S4.4: Data is weighted according to the input weight value X = {X1...X k},in That is, the weighted strain energy value corresponding to unit k.

[0023] Furthermore, it is applicable to complex ship structures and improves the optimization efficiency and accuracy of damping installation.

[0024] Furthermore, it also includes verifying the suppressing effect of the damping material on the sound radiation by comparing the sound radiation levels before and after laying the damping material.

[0025] The beneficial effects of the present invention are as follows:

[0026] The present invention has a compact and reasonable structure and is easy to operate. It realizes the optimal design of the damping installation of ship structures by adopting advanced means such as full three-dimensional dynamic model, modal identification method and construction of unit damping efficiency data set. Compared with traditional methods, this method has higher accuracy and efficiency, can more comprehensively reflect the damping structure's ability to suppress vibration and noise, and provides a more efficient and accurate damping installation optimization method for the engineering and academic communities.

[0027] At the same time, the present invention also has the following advantages:

[0028] 1. This method uses a full three-dimensional dynamic model to perform acoustic elastic analysis on the ship structure, which can more accurately simulate the sound radiation of the ship under the actual working load. Compared with traditional methods, the full three-dimensional model provides more detailed and accurate data, which provides a more reliable basis for the optimization of damping installation. Through this method, we can have a more comprehensive understanding of the damping structure's ability to suppress vibration and noise, thereby providing an important reference for subsequent damping design. In addition, the full three-dimensional dynamic model can also reflect the dynamic response of the structure under different working conditions, providing more abundant information for the optimization of damping installation, and helping to achieve better vibration and noise reduction effects.

[0029] 2. This method can accurately identify the modes that contribute most to sound radiation through the modal identification method, providing a clear target for damping installation. Compared with the traditional method that relies on experience to judge the installation location, this method ensures the pertinence and effectiveness of damping installation through scientific analysis and calculation. At the same time, by constructing a data sample set of structural unit strain energy and normalizing and weighting the data, this method can more accurately evaluate the contribution of different units to sound radiation and provide a scientific basis for damping installation. This data-based optimization method greatly improves the accuracy and efficiency of damping installation.

[0030] 3. This method constructs a unit damping efficiency data set to evaluate the strain energy loss of different units after increasing the damping thickness, providing a basis for optimizing the damping installation position. Compared with traditional methods, this method can more accurately determine the area and thickness of the damping installation and maximize the utilization of damping materials. At the same time, by forming a generalized damping matrix and conducting three-dimensional acoustic elastic analysis, this method can verify the optimized damping installation effect and ensure that the expected vibration reduction and noise reduction goals are achieved. This method based on optimization design and verification not only improves the effect of damping installation, but also reduces the construction difficulty and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a logic block diagram of the present invention.

[0032] Figure 2 It is the force diagram of the original structural model in the present invention.

[0033] Figure 3 This is a structural diagram of the model after modal analysis in the present invention.

[0034] Figure 4 This is a structural diagram of the model after damping optimization in the present invention.

[0035] Figure 5 It is a line graph comparing the acoustic radiation of the structure under excitation load after the damping material is laid in the present invention and the acoustic radiation of the structure without treatment. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is described below in conjunction with the accompanying drawings.

[0037] like Figure 1-Figure 5 As shown, this embodiment discloses a method for laying low-noise damping of underwater structures based on three-dimensional acoustic elasticity of ships, comprising the following steps:

[0038] S1: Figure 2 As shown in the figure, a full three-dimensional dynamic model is established for the structure, and a three-dimensional acoustic elastic analysis of the ship is carried out for the actual working load excitation. The structural acoustic radiation under the original structural excitation load is obtained. Through the full three-dimensional dynamic model, the acoustic radiation of the ship under the actual working load can be simulated more accurately, and the damping structure's ability to suppress vibration and noise can be more comprehensively reflected, providing basic data for subsequent damping layout optimization;

[0039] S2: Figure 3As shown in the figure, the acoustic radiation characteristic frequency modal identification method based on the ship three-dimensional acoustic elastic method is adopted. The radiated acoustic power of a single mode is approximately solved according to the principal coordinate response of each mode and the attached water damping. Through the modal identification method, the mode that contributes more to the acoustic radiation can be identified, providing a target for the subsequent damping installation. The modes of interest and their corresponding weight coefficients are identified through modal calculation and modal analysis, providing an important reference basis for the subsequent damping design.

[0040]

[0041] Where: P(ω) is the radiated acoustic power, q is the principal coordinate response, B is the attached water damping matrix, and the superscript “*” indicates conjugation;

[0042] Figure 3 In the present invention, after the model is subjected to modal analysis, the principal coordinate response is marked on the structure, and the modal identification method is used to identify the modes that contribute most to the sound radiation, providing a target for the subsequent damping installation.

[0043] S3: Construct the characteristic mode of interest based on actual engineering needs mode = {mode1...mode i}, corresponding weight A={A1...A i} and the amount of damping material laid m0. According to the actual engineering requirements, the characteristic modes that need to be concerned and their weights, as well as the amount of damping material laid, are determined to provide clear guidance for the optimization process. This step is the premise for the damping material parameter design and the damping structure unit design and layout. By determining the characteristic modes of concern and their weights, as well as the amount of damping material laid, a clear direction is provided for the subsequent optimization design;

[0044] S4: After constructing the concerned modes and corresponding weight coefficients based on actual engineering needs, we can construct a data sample set of structural unit strain energy, output the unit modal strain energy of each unit of the structure, and perform normalization and weighting processing. By constructing a data sample set of structural unit strain energy and normalizing and weighting the data, we can more accurately evaluate the contribution of different units to sound radiation and provide a scientific basis for damping installation. The specific steps can be briefly described as follows:

[0045] S4.1: Based on the modal characteristics of interest, output the modal strain energy of the structure's required layout area elements This step corresponds to "unit modal strain energy analysis", which reflects the energy distribution of each part of the structure under a specific mode by analyzing the modal strain energy of each structural unit;

[0046] S4.2: Volume normalization of the element modal strain energy, This step is to further process the element modal strain energy in order to more intuitively compare the contribution of different elements in vibration reduction effect;

[0047] S4.3: If the number of modes of interest is greater than 1, energy normalization is required. where sum(elen_all i ) is the sum of the strain energies of all units in the corresponding modal structure. This step is to ensure that the contribution of each unit to the sound radiation can be accurately evaluated in the case of multi-modes;

[0048] S4.4: Data is weighted according to the input weight value X = {X1...X k},in That is, the weighted strain energy value of the corresponding unit k. This step is to weight the data according to the mode of interest and its weight to more accurately reflect the importance of each unit in the vibration reduction effect;

[0049] S5: Construct a unit damping efficiency data set, and output the increment of the strain energy loss of all units in the design area for each additional unit damping thickness unit area structure unit. By constructing the unit damping efficiency data set, the strain energy loss of different units after increasing the damping thickness can be evaluated, providing a basis for optimizing the damping laying position. This step corresponds to a part of the design and layout of the damping structural unit. By evaluating the strain energy loss of different units after increasing the damping thickness, a basis is provided for optimizing the damping laying position.

[0050] S6: Figure 4 As shown, the damping thickness of the corresponding area is output from large to small according to the damping loss efficiency of the unit damping efficiency data set. According to the set damping material weight constraint, the structural damping laying area data set is constructed. According to the damping loss efficiency and damping material weight constraint, the optimal damping laying area and thickness can be determined to maximize the use of damping materials. This step corresponds to the "damping structure unit layout" and "unit thickness setting" in the damping structure unit design and layout. By optimizing the damping laying area and thickness, it is ensured that the damping material can give full play to its vibration reduction effect, while considering the construction difficulty and cost factors;

[0051] like Figure 4 As shown in the figure, the structural model after the damping laying optimization is displayed, where the red part indicates the area where the damping material is laid. The damping thickness of the corresponding area is output from large to small according to the damping loss efficiency of the unit damping efficiency data set. By optimizing the damping laying area and thickness, it is ensured that the damping material can give full play to its vibration reduction effect.

[0052] S7: Figure 5As shown, a generalized damping matrix [b] is formed based on the modal strain energy method, and a three-dimensional acoustic elastic analysis of the ship is carried out; the structural acoustic radiation under the excitation load of the structure after laying is obtained. By forming a generalized damping matrix and carrying out a three-dimensional acoustic elastic analysis, the optimized damping laying effect can be verified to ensure that the expected vibration reduction and noise reduction goals are achieved. This step corresponds to a part of the damping structure design optimization and verification. By forming a generalized damping matrix and carrying out a three-dimensional acoustic elastic analysis, the optimized damping laying effect is verified to ensure that the damping structure achieves the best vibration reduction effect under specific working conditions.

[0053] Figure 5 In the figure, a generalized damping matrix is ​​formed based on the modal strain energy method [b], and after carrying out the three-dimensional acoustic elastic analysis of the ship, the acoustic radiation of the structure under the excitation load after the damping material is laid is obtained. The blue curve in the figure represents the acoustic radiation level after the damping material is laid, while the black curve represents the acoustic radiation level when the damping material is not laid. By comparing the two curves, we can intuitively see the inhibitory effect of the damping material on the acoustic radiation, verifying the effectiveness of the optimized damping laying scheme.

[0054] This method uses a full three-dimensional dynamic model to perform acoustic elastic analysis on the ship structure, which can more accurately simulate the sound radiation of the ship under the actual working load. Compared with traditional methods, the full three-dimensional model provides more detailed and accurate data, which provides a more reliable basis for the optimization of damping installation. Through this method, we can have a more comprehensive understanding of the damping structure's ability to suppress vibration and noise, thereby providing an important reference for subsequent damping design. In addition, the full three-dimensional dynamic model can also reflect the dynamic response of the structure under different working conditions, providing more abundant information for the optimization of damping installation, and helping to achieve better vibration and noise reduction effects.

[0055] This method can accurately identify the modes that contribute most to sound radiation through the modal identification method, providing a clear goal for damping installation. Compared with the traditional method that relies on experience to judge the installation location, this method ensures the pertinence and effectiveness of damping installation through scientific analysis and calculation. At the same time, by constructing a data sample set of structural unit strain energy and normalizing and weighting the data, this method can more accurately evaluate the contribution of different units to sound radiation and provide a scientific basis for damping installation. This data-based optimization method greatly improves the accuracy and efficiency of damping installation.

[0056] This method constructs a unit damping efficiency data set to evaluate the strain energy loss of different units after increasing the damping thickness, providing a basis for optimizing the damping installation location. Compared with traditional methods, this method can more accurately determine the area and thickness of the damping installation and maximize the use of damping materials. At the same time, by forming a generalized damping matrix and conducting three-dimensional acoustic elastic analysis, this method can verify the optimized damping installation effect and ensure that the expected vibration reduction and noise reduction goals are achieved. This method based on optimization design and verification not only improves the effect of damping installation, but also reduces the construction difficulty and cost.

[0057] In summary, this method achieves the optimal design of ship structure damping by adopting advanced means such as full three-dimensional dynamic model, modal identification method and construction of unit damping efficiency data set. Compared with traditional methods, this method has higher accuracy and efficiency, and can more comprehensively reflect the damping structure's ability to suppress vibration and noise, providing a more efficient and accurate damping optimization method for the engineering and academic communities.

[0058] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A method for laying low noise damping for underwater structures based on three-dimensional acoustic elasticity of ships, characterized in that: include: S1: Establish a full three-dimensional dynamic model for the structure, conduct three-dimensional acoustic elastic analysis of the ship based on the actual working load excitation, and obtain the structural acoustic radiation under the original structural excitation load; S2: The acoustic radiation characteristic frequency mode identification method based on the ship's three-dimensional acoustic elastic method is adopted; S3: Construct the characteristic modes of interest based on actual engineering needs, corresponding weights and damping material laying; S4: After constructing the mode of interest and the corresponding weight coefficient based on actual engineering needs, we can construct a data sample set of structural unit strain energy, output the unit modal strain energy of each unit of the structure, and perform normalization and weighting processing; S5: construct a unit damping efficiency data set, and output the increment of the strain energy loss of the structural unit in each unit damping thickness unit area of ​​all units in the design area; S6: Output the damping thickness of the corresponding area according to the damping loss efficiency from large to small for the unit damping efficiency data set, and construct the structural damping laying area data set according to the set damping material weight constraint; S7: Based on the modal strain energy method, a generalized damping matrix is ​​formed [b], and a three-dimensional acoustic elastic analysis of the ship is carried out to obtain the structural sound radiation under the excitation load of the structure after laying.

2. A method for laying low noise damping for underwater structures based on three-dimensional acoustic elasticity of ships as claimed in claim 1, characterized in that: In S2, the principal coordinate response of each mode and the attached water damping are used to approximate the radiated sound power of a single mode. Where P(ω) is the radiated acoustic power, q is the principal coordinate response, and B is the attached water damping matrix. The superscript "*" indicates conjugation.

3. A method for laying low noise damping for underwater structures based on three-dimensional acoustic elasticity of ships as claimed in claim 2, characterized in that: In S3, the characteristic mode of interest is constructed based on actual engineering needs. mode={mode1...mode i }, corresponding weight A={A1...A i } and the amount of damping material laid m0.

4. A method for laying low noise damping for underwater structures based on three-dimensional acoustic elasticity of ships as claimed in claim 3, characterized in that: The processing method in S4 further includes the following steps: S4.1: Based on the modal characteristics of interest, output the modal strain energy of the structure's required laying area elements S4.2: Volume normalization of the element modal strain energy, S4.3: If the number of modes of interest is greater than 1, energy normalization is required. where sum(elen_all i ) is the sum of the strain energies of all elements in the corresponding modal structure; S4.4: Data is weighted according to the input weight value X = {X1...X k },in That is, the weighted strain energy value corresponding to unit k.

5. The method for laying low noise damping for underwater structures based on three-dimensional acoustic elasticity of ships according to claim 1, characterized in that: It is suitable for complex ship structures and can improve the optimization efficiency and accuracy of damping installation.

6. A method for laying low noise damping for underwater structures based on three-dimensional acoustic elasticity of ships as claimed in claim 1, characterized in that: It also includes verifying the effect of damping material on suppressing sound radiation by comparing the sound radiation levels before and after laying the damping material.

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